He told BBC Sunday Politics Wales: “It took me six hours and 15 minutes in the car to get here. It should have taken three and half to four.

“That has nothing to do with professionalism. What is does have to do with is a country in which the population is going through the roof, chiefly because of open door immigration and the fact the M4 is not as navigable as it used to be.

.@Nigel_Farage If even the Mail and Telegraph are accusing you of being a massive racist, maybe you ought to have a think.

”In all these years in UKIP that’s probably about the third event out of a thousand that I haven’t made in time.”

Labour was first to criticise Farage’s audacious excuse, calling it “absurd”.

“Remarks like these are what makes Farage so dangerous,” said then-Shadow Welsh secretary Owen Smith. “It is clearly absurd to suggest heavy traffic on the M4 is caused by immigration, but through the laughter at his silly comments you can hear Ukip’s dog-whistle politics of division.”